As an example of using SnO.sub.2 or an Sn compound as an active material of a lithium battery, JP-A ("JP-A" means unexamined published Japanese patent application) No. 219465/1987 discloses adding SnO.sub.2 to .alpha.-Fe.sub.2 O.sub.3, which is a negative-electrode (anode)-active material of the secondary battery, with a preferable addition amount of SnO.sub.2 being 0.5 to 10 mol %. Additionally, JP-A No. 136131/1970 discloses that LicoO.sub.2 -series compounds, as positive-electrode (cathode)-active materials, provide high energy density.
On the other hand, these active materials are powdered materials, and therefore they are mixed and kneaded with a conducting agent, a binder, and so on, to obtain a mixture, and then the mixture is coated on a support.
In this case, these active materials, having a large grain size, have caused some problems, such as damage to the support at a coating and scratching on a separator when the active materials are rolled with a negative electrode and a separator, which results in short-circuiting. A method of solving such problems is described in JP-A No. 62713/1993. JP-A No. 304664/1989 discloses a nonaqueous electrolytic solution battery employing LiCoO.sub.2 having an average grain size of 10 to 150 .mu.m, but the coating property of the compound is not satisfactory. JP-A No. 33260/1992 discloses a method of using LiCoO.sub.2 having an average grain size of not more than 0.5 .mu.m. The coating property of the compound is satisfactory, but the self-discharge characteristics and charge/discharge cycle characteristics are inferior. Further, JP-A No. 94822/1993 discloses Li.sub.1.03 Co.sub.0.92 Sn.sub.0.02 O.sub.2 having a specific grain size distribution, but the self-discharge characteristics, the charge/discharge cycle characteristics, and the coating property are not completely satisfactory.